In wellbore operations, packers may be used to control migration of fluids outside a liner installed in the wellbore. For example, packers may be installed in the annulus between the liner and the wellbore wall to deter migration of the fluids axially along the annulus.
Packers may be set by hydraulics. Oftentimes, the hydraulic pressure is introduced through the tubular string on which the packer is installed and is communicated to the packer's hydraulically actuated system by a port through the tubular wall, also called a mandrel, on which the packing elements are installed. The port extends through the tubular wall and provides communication from the tubing string inner diameter and the hydraulic cylinder for the packer. There are seals within the cylinder that contain and direct the hydraulic pressure.
One of the disadvantages of hydraulically set mechanical packers is the port in the tubular wall. In pressuring applications, for example, when fracing a well and/or pressurizing the liner, the hydraulic cylinders are subjected to the pressures being utilized and in some cases, empty cyclic pressures, which results in cylinders moving and seals moving under pressure situations, which can be in the range of 10,000 psi and at fairly high elevated temperatures. Under such conditions, the ports in the casing string for setting chambers introduce a point of weakness and potential failure. Additionally, in high temperature applications, seals, and the like, can degrade, and a leak path can form through the port in the mandrel and into the annulus, past the problematic seals.
Accordingly, there remains a need for improvements in the art.